Delhi woke up to bone-chilling cold on Monday and a dense layer of fog enveloped the city and its adjoining areas, making the visibility zero at several places. As many as four flights have been cancelled, while 19 others have been diverted due to low visibility at the Indira Gandhi International (IGI) Airport, officials said.

"Low visibility procedures are still in progress. All CAT III B compliant pilots are able to operate. Departures may be impacted if Runway Visibility Range falls below 125m. Please get in touch with the airline concerned for updated flight information. Any inconvenience caused is deeply regretted," said Delhi Airport in a statement.